AudioService: Go back to virtual SCO calls on multi-function units

Direct raw audio channels to these HFP devices is resulting in
dead audio on hangouts, on all devices. Until that is figured
out and/or fixed, go back to establishing a virtual call to open
up the audio channels

Change-Id: I794e75eed96ac09cfbb1c9d28c90d3161cfb7149
Merge "AudioService: Go back to virtual SCO calls on multi-function units" into jb4.3